Plants get stressed too… ‘master regulator’ gene discovery sheds new light on response

A single, critical gene that’s responsible for modulating plants’ responses to stress has been identified for the first time. The previously uncategorised gene could prove crucial for improving resilience and protecting yields as climate change exacerbates environmental pressure on plants.

With the results of recent research published in the journal Frontiers in Plant Science, the project was conducted by a team from the University of Delaware and Syracuse University. Understanding the newly identified gene, known as SDA1, could help improve crop resistance to stressors ranging from drought to flood, fungus, pathogens and salinity.

"SDA1 is actually a very small gene, but it's critical because it controls both biotic and abiotic responses simultaneously within the plant," said Aditya Dutta, Assistant Professor in the Department of Animal and Food Sciences at Delaware University.

Dutta began his research by looking at the gene expression arrays of plants after exposing them to more than 20 stressors. Further investigation saw Dutta discover that SDA1 acts as a ‘master regulator’ by remediating reactive oxygen species (ROS).

“It's a gene that regulates other genes, affecting both the biotic and abiotic response, and making the plant hardier on both fronts,” explained Dutta.

The relationship between SDA1 and salicylic acid – which controls a large portion of biotic responses, so much so that it’s often sprayed onto plants in commercial contexts to boost their immune responses – has proven key to the research.

"What I found was that not only does SDA1 interact with salicylic acid, but if you remove SDA1 it affects the amount of salicylic acid that a plant can hold. If it can't hold that much salicylic acid, it basically reduces the plant's ability to fight off infection,” Dutta said.

Investigating SDA1 further, the researchers looked for genes or proteins that perform similar functions. Finding none, they set about exploring the entire gene sequence to determine what makes SDA1 unique. This led to the identification of an important, seven amino acid-domain.

"When we started looking at this domain, our initial hunch was that it was probably important because it was conserved; but then we went back and we mutated each amino acid, one at a time, to see which ones were important," said Dutta.

"We found that you need the entire domain. There is functional relevance for these seven amino acids, as this domain is what controls the response against both biotic and abiotic stress."

The research is expected to have broad application, since the seven amino acid-domain is present in most plants that have been sequenced so far, including many commercial crops. As temperatures rise, salinity changes, and crops require increasing irrigation to maintain and boost production, the need for resilient species and cultivars continues to rise.

It is hoped by selecting cultivars and strains that express SDA1 and its seven amino acid-domain in ways which make them more resistant to stress, growers can increase the resilience of their plants.